Outside the Cell

On a flat bilayer, the spatial regulators of cell division can form a variety of patterns. Dissecting how these patterns form outside of the cell is unravelling the oscillatory mechanism used inside the cell. (Vecchiarelli et al., PNAS 2016)

Simulations

A Diffusion-Ratchet Model for Bacterial DNA Segregation and Transport

No Surface Confinement

Transport of Surface-Confined Cargo

Segregation of Surface-Confined Cargo

Animations by Ethan Tyler

ParA protein (green) binds the nucleoid and the ParB protein (red) binds the cargo. ParB releases ParA around the cargo, creating a ParA gradient. Without surface confinement, the cargo can diffuse away. In a bacterial cell, the narrow gap between membrane and nucleoid confines the cargo to the nucleoid. Cargo transport is directed by ParA contacts at its movement front and reversal is suppressed by the lack of ParA behind it. Replicated cargo segregate as they chase ParA in opposite directions. (Vecchiarelli et al., PNAS 2014)